Purification of organic bodies



UNITED STATES PATENT OFFICE I 1,957,484 PURIFICATION OF ORGANIC BODIES Adolph Zimmerli and Robert 0. Lyon, New Brunswick, N. J.; assignors, by mesne assignments, to E. I. du Pont de Nemours 8: Company, a corporation of Delaware No Drawing. Application May 27, 1931,

Serial N0. 540,499

. 11 Claims. (01. 202-46) This invention relates to purification of noring of the crystals of quinone to' the surface of mally solidprganic substances by distilling with the condenser. For best results, the organic steam. In its more specific aspect this invention solvent should be fed in gradually as the distilrelates to a process of purifying quinone by dislation proceeds. Thus, although the total quantilling the same with steam at reduced pressure. tity of solvent employed is about sufficient to 60 In our U. S. Patent No. 1,883,284, issued Octodissolve all the quinone distilled over, its con-. ber 18, 1932, we have described a method of puricentration in the boiling aqueous mixture is at fymg quinone by distilling the reaction mass in no time large enough to form with water a conwhich quinone is produced and which contains stant boiling mixture. Another way of stating considerable quantities of water, at a temperathis, is that the solvent should be fed in at such 65 tureof about 50 to 60 C. and under a vacuum a slow rate as would be insufiicient at any time ove the boiling liquid of about 2'7 inches; The distilled vapors are to saturate the space ab condensed to give a saturated aqueous quinone with the vapors'of the solvent. solution containing crystals of quinone which The following example will serve further to 15 may be separated by filtration. While the above illustrate our invention, without, however, 1im- 70 process constitutes a most economical method iting the same. Parts given are parts by weight. for the recovery of pure quinone from its crude E l 1 state, it suffers from the drawback that the conmm!) 8 V densed quinone tends to form a cake on the con- ,90 parts of crude quinone, as obtained for indensing surface, thereby impairing the heat stance, by oxidizing aniline with manganese di- 7 transfer. oxide in known manner, are suspended in 2000 It is accordingly an object of this invention to parts of water in a closed vessel provided with a improve the process of steam distillation of dropping funnel andconnected through a conquinone whereby to avoid the-troubles of caking denser to a receiver, which in turn is connected in the condenser. to a vacuum pump. The vessel is -heated to about so Otherand further important objects of this to C., anda vacuum of about 24 to 26 invention will appear as the description proinches of mercury is applied to the system. As ceeds. the mixture in the vessel starts boiling, chloro- We have found that the above drawback can benzol is slowly dripped in through the drop- 30 be avoided by adding to the mixture of crude ping funnel, at such a slow rate that it is evapg5 quinone in water an organic solvent for quinone orated about as fast as introduced, and that a which is immiscible with water, and which is in total of 800 parts are introduced during the itself volatile with steam. The presence of the course of the distillation. The vapors pass into organic solvent in the distillate prevents the the condenser, and being liquefied flow into the 35 quinone from settling and caking upon the walls receiver. If any quinone begins to settle out 99 of the condenser. ThdistiHate separates into in the condenser, the rate of supply of chlorotwo layers-an aqueous layer and an organic benzol is slightly increased, whereupon the subsolvent layer--each of which contains quinone limed quinone is immediately redissolved and dissolved therein. The pure quinone may then carried into the receiver. The condensate sepabe recovered from these solutions in any wellrates into two layers. The upper, aqueous layer known manner. contains about 1% of quinone dissolved therein,

The optimum proportion of organic solvent to while the lower, chlorobenzol layer contains about be used depends on the solvent, and can be 10% of quinone. After separating the two layers readily determined for each solvent by a little in a separating column, the aqueous layer is ex- 45 experimentation. Large proportions of the ortracted with fresh chlorobenzol, which may then ganic solvent are not detrimental, but if the be joined to the main chlorobenzol layer. The quantity used is large enough to form a constant chlorobenzol-quinone solution is subjected to i in mix u wi h w e q non will b partial distillation to concentrate the same and carried over than would be the case with water t recover th b lk of th chlorobenzol, After 59 alone. Consequently, the efi'iciency of the procabout of the latter have been distilled off, ess suffers. 'On the other hand, too little orthe concentrated solution is cooled to about 10 C. ganic solvent may not prevent completely the or lower, and the pure, yellow crystals of quinone formation of cake in the condenser. The most separating are filtered off and dried with air. economical proportion to be used, therefore, is The yield of quinone is about 90% of the crude 55 that which is just sufiicient to prevent the stickmass.

. our invention is not limited to such details. For

instance, instead of chlorobenzol, any organic liquid which is a good solvent for quinone, immiscible with water, and volatile with steam may be used. Also, instead of introducing such liquid into the still, it may be introduced directly intothe condenser. I

It will be furtherunderstood that our novel method of purification is applicable to other organic compounds which have a high melting point, that is, above 100 C., and which are volatile with steam; for instance, camphor, benzoic acid, and the like, and which would other: wise offer difficulties in distillation due to their tendency to cake upon the surface of the condenser. V i

We claim: or

-1. The process of purifying quinone, which comprises steam distilling a crude quinone mass as obtainable in the manufacture of quinone under reduced pressure in the presence of an organic solvent for quinone which is immiscible with Water but volatile with steam, and recovering quinone from the distillate.

The process of purifying quinone, which comprises steam distilling a crude quinone mass as obtainable in the manufacture of quinone under reduced pressure, while gradually feeding into the 7 still an organic solvent for quinone which is immiscible with water but volatile with steam, and recovering quinone from the distillate.

3. The process of purifying quinone, which comprises steam distilling crude quinone under reduced pressure, while gradually feedinginto the still an organic solvent for quinone which is immiscible with water but volatile with steam, said solvent being fed in at a rate insufiicient to form within the still a constant boihng mixture with the water therein present.

4. The process of purifying quinone, which comprises steam distilling crude quinone under reduced'pressure, while gradually feeding into the still an organic solvent for quinonewhich is immiscible with water but volatile with steam, said solvent being fed in at a rate insufiicient to saturate'the space above the boiling liquid with the vapors of said solvent.

5. The process of purifying crude quinone which comprises distilling the same with steam and in the presence of chlorobenzol under reduced pressure and at a temperature of about 50 to 60" C., separating the condensate into an aqueous layer and a chlorobenzol layer, and recovering quinone from the chlorobenzol layer.

6 The process of recovering an aromatic compound which melts above 100 C. and which is volatile with steam, from aicrude mass of which said compound is the major organic constituent, which comprises steam distilling said compound and condensing the vapors in the presence of an added organic compound which is a solvent for the compound being purified but immiscible with Water. 7 7

7. The process of recovering a terpene. compound which melts above. 100 C. and which is volatile with steam, from a crude mass of which said compound is the major organic constituent, which comprises steam distilling said compound and condensing the vapors in the presence of an added organic compound which is a solvent for the compound being purified but immiscible with water.

8. The process of recovering quinone from a crude mass of which it is the major organic constituent, which comprises steam distilling said ;mass and condensing the vapors in the presence '-mass and condensing the vapors in the presence of an organic liquid which is a solvent for camphor but immiscible with Water.

11. The process of recovering an organic compound selected from the group consisting of aromatic compounds and terpene compounds, which melt above 100 C. and are volatile With steam, from a crude mass of which said compound is the major organic constituent, which comprises distilling said compound and condensing the vapors in the presence of an added organic compound which is a solvent for the compound being purified but immiscible with water.

ADOLPH ZIMMERLI ROBERT C. LYON. 

